Dam laminate isolation substrate

ABSTRACT

An apparatus includes a lead frame, a dam and adhesive on portions of the lead frame, and an integrated circuit die having a portion on the dam and another portion on the adhesive. The lead frame can include two portions, or two lead frames. The dam can bridge a space between the two lead frames. The dam can be smaller than the integrated circuit die in at least a width dimension of the dam relative to a width dimension of the integrated circuit die, providing that the integrated circuit die overhangs the dam on each side of the width dimension of the dam. Adhesive is located between the integrated circuit die and each lead frame, adjacent to and on each side of the dam. The dam prevents adhesive from spreading into the space between the lead frames.

BACKGROUND

Semiconductor packages often comprise a semiconductor die attached to alead frame and electrically connected to bond fingers of the lead frame.The semiconductor the is attached to the lead frame by an adhesiveresin. Adhesive resins for attaching the semiconductor die to the leadframe include epoxy-based adhesives, acrylate-based adhesives, siliconesand polyimides.

Although such adhesives are fairly viscous, they exhibit a tendency tobleed or spread into a space between lead frames of the substrate,possibly causing bridging and/or arcing. This spreading or bleeding ofadhesive resin into the space between lead frames of the substrateencroaches upon the HV-LV split DAP spacing and effects properclearances of M4/5/6 trace-DAP.

There exists a continuing need for a reliable and simple basis forsolving the adhesive resin bleed problem that causes damage to, shortcircuiting of, or poor isolation performance of, the semiconductorpackage.

SUMMARY

In one aspect, an apparatus includes a lead frame, a dam and adhesive onportions of the lead frame, and an integrated circuit die having aportion on the dam and another portion on the adhesive. The lead framecan include two portions, or two lead frames. The dam bridges a spacebetween the two lead frames. The dam can be smaller than the integratedcircuit die in at least a width dimension of the dam relative to a widthdimension of the integrated circuit die, providing that the integratedcircuit die overhangs the dam on each side of the width dimension of thedam. Adhesive is located between the integrated circuit die and eachlead frame, adjacent to and on each side of the dam. The dam preventsadhesive from spreading into the space between the lead frames. The damcan be a dry film, for example, a PSR800 AUS410 dry film.

In another aspect, an apparatus includes a lead frame, a dam andadhesive on portions of the lead frame, and an integrated circuit diehaving a portion on the dam and another portion on the adhesive. In thisaspect, the dam is smaller than the integrated circuit die in a widthand length dimension of the dam relative to the integrated circuit die,over at least a portion of the dam and the integrated circuit die, wherethe integrated circuit die overhangs the dam in each location where thedam is smaller than the integrated circuit die in the width or thelength dimension. The dam and the integrated circuit die bridge a spaceadjacent to a side of the lead frame. Adhesive is located between theintegrated circuit die and the lead frame, adjacent to and on each sideof the dam, due to the dam being smaller than the integrated circuit diein the width and the length dimension. The dam prevents adhesive fromspreading into the space adjacent to the side of the lead frame.

In a further aspect, a method of manufacturing an integrated circuitpackage includes the steps of placing an integrated circuit die on adam, the dam being smaller than the integrated circuit die in at least awidth dimension of the dam relative to a width dimension of theintegrated circuit die, where the integrated circuit die overhangs thedam on each side of the width dimension of the dam. The integratedcircuit die and the dam are placed on a two portion lead frame, wherethe dam and the integrated circuit die bridge a space between the twoportions of the lead frame. Adhesive is located between the integratedcircuit die and the lead frame, adjacent to and on each side of the dam,due to the dam being smaller than the integrated circuit die in at leastthe width dimension. The dam prevents the adhesive from spreading intothe space between the two portions of the lead frame. The dam can beattached to the integrated circuit die prior to the placing of theintegrated circuit die and the dam on the two portions of lead frame. Inthis aspect, manufacturing the integrated circuit package could includeconnecting bond pads of the integrated circuit die to bond fingerconnections of the integrated circuit package, and encapsulating theintegrated circuit die in the integrated circuit package.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed description of various examples, reference will now bemade to the accompanying drawings in which:

FIG. 1 illustrates a cross-section view of a semiconductor integratedcircuit package;

FIG. 2 illustrates a cross-section view of another semiconductorintegrated circuit;

FIG. 3 illustrates a cross-section view of one aspect of a semiconductorintegrated circuit package in accordance with various examples;

FIG. 4 illustrates a cross-section view of another aspect of asemiconductor integrated circuit package in accordance with variousexamples;

FIG. 5 illustrates a perspective view of one aspect of a lead frame inaccordance with various examples;

FIG. 6 illustrates a perspective view of one aspect of a lead frame witha S/R dam thereon, in accordance with various examples;

FIG. 7 illustrates a perspective view, from another end, of the aspectof a lead frame with a S/R dam thereon shown in FIG. 6;

FIG. 8 illustrates a perspective view, from an underside, of one aspectof an integrated circuit die, relative to a S/R dam thereon, withportions of a lead frame thereabout, in accordance with variousexamples; and

FIG. 9 illustrates a perspective view of one aspect of an integratedcircuit die above a S/R dam, all relative to portions of a lead frame,in accordance with various examples.

DETAILED DESCRIPTION

Certain terms are used throughout the following description and claimsto refer to particular system components. As one skilled in the art willappreciate, different parties may refer to a component by differentnames. This document does not intend to distinguish between componentsthat differ in name but not function. In the following discussion and inthe claims, the terms “including” and “comprising” are used in anopen-ended fashion, and thus should be interpreted to mean “including,but not limited to . . . .”

FIG. 1 illustrates a cross-section view of a semiconductor integratedcircuit package 110 having a lead frame 112, an integrated circuit die(or silicon semiconductor chip or laminate) 114, a plurality of bondfingers 116, a plurality of bond pads 118, and bond wires 120.

The bond fingers 116 generally extend about a perimeter of a sidesurface of the die 114 attached to the lead frame 112. The bond fingers116 are electrically connected to the bond pads 118 on a surface of thedie 114 by respective bond wires 120.

The lead frame 112 can include two portions or sides 122, 124, or twolead frames 122, 124 (e.g., a high voltage (HV) side 122 and a lowvoltage (LV) side 124). In the cross-section view of FIG. 1, a spaceexists between the two portions, or between the HV side 122 and the LVside 124. This space is referred to as a pad-to-pad (P2P) space 126. TheP2P space 126 runs longitudinally, along a longitudinal axis L of theintegrated circuit package 110, between internal edges (pads) of the twoportions 122, 124 (e.g., between the HV side 122 and the LV side 124).In FIG. 1, longitudinal axis L runs into and out of the page, as shown.

The integrated circuit die 114 is attached to the lead frame 112 by anadhesive resin 130. As shown in FIG. 1, the adhesive resin 130 has atendency to bleed or spread into the space between the HV side 122 andthe LV side 124 (or the two portions) of the lead frame 112. Excessiveresin 130 in this space can cause bridging and/or arcing. Note thebridging shown in FIG. 1.

As shown in FIG. 2, the adhesive resin (e.g., conductive die attach D/A)130 can spread or bleed into the P2P space 126 after die 114 attachmentto the lead frame 112 and shorten the P2P space (or split) 126 betweenthe HV side 122 and the LV side 124, encroaching upon and effectingproper clearances of M4/5/6 trace-DAP spacing (e.g., B, C, E) shown inFIG. 2. The adhesive resin (e.g., conductive die attach D/A) 130sometimes prefers contact with the die 114, instead of the lead frame112, due to good wetting ability between the adhesive resin 130 and asolder resist of the die 114.

FIG. 3 illustrates a cross-section view of a semiconductor integratedcircuit package 110, such as that shown in FIG. 1, with a solder resist(S/R) dam 350 located between the integrated circuit die 114 and thelead frame 112. The addition of the S/R dam 350, between the die 114 andthe lead frame 112, provides control of the location of the adhesiveresin 130 to ensure isolation design parameters.

As shown in FIG. 3, the S/R dam 350 bridges the space 126 between thetwo portions of the lead frame 112 (e.g., the dam spans from the HV side122 to the LV side 124 of the lead frame 112), while residing on the HVside 122 and the LV side 124 of the lead frame 112. In one aspect, theS/R dam 350 can be a dry film. In another aspect, the S/R dam 350 isPSR800 AUS410 dry film. The S/R dam 350 could generally be between 25and 30 microns in thickness (e.g., in vertical height as shown in FIG.3). In a further aspect, the S/R dam 350 can first be attached to theintegrated circuit die 114, then the die 114 with the dam 350, together,are attached to the lead frame 112. In any event, or in any method offabrication, the S/R dam 350 is located between the integrated circuitdie 114 and the lead frame 112.

In one aspect, the dam 350 lies within the inside of the die 114 area.In another aspect, the dam 350 is smaller than the integrated circuitdie 114 in at least a width dimension of the dam 350 and of theintegrated circuit die 114. In a further aspect, the integrated circuitdie 114 overhangs the dam on each side of the width dimension of the dam350 and of the integrated circuit die 114, when the dam 350 is attachedto, or is arranged relative to, the die 114. As shown in FIG. 3, thisarrangement creates a gap between the die 114 and each of the twoportions of the lead frame 112 (e.g., each of the HV side 122 and the LVside 124 of the lead frame 112), on each side of the S/R dam 350. Thegap is filled by adhesive resin 130. The S/R dam 350 limits the locationof the adhesive resin 130 when the die 114 is attached to the lead frame112. In this way, the dimension of the dam 350 relative to the die 114(and the resulting dimension of the overhang) controls the location ofthe die adhesive to desired parameters. This better ensures isolationdesign parameters of the semiconductor, thereby providing higherefficiency and isolated power by improving space utilization. In certaininstances, use of the S/R dam during semiconductor integrated circuitpackage fabrication can eliminate the need for die adhesive extrusioninspection during fabrication.

FIG. 4 illustrates a cross-section view of a semiconductor integratedcircuit package 110, with the solder resist (S/R) dam 350 locatedbetween the integrated circuit die 114 and the lead frame 112. Theaddition of the S/R dam 350, between the die 114 and the lead frame 112,where the S/R dam 350 has a width as shown in the FIG. 4 cross-section,provides control of the location of the adhesive resin 130 to ensuredesired isolation design parameters.

FIG. 5 illustrates a perspective view of a lead frame 112 including twolead frames 122, 124, or two portions 122, 124 of a lead frame (e.g., ahigh voltage (HV) side 122 and a low voltage (LV) side 124). FIG. 5provides a perspective view (relative to the cross-section view of FIG.3), showing the P2P space 126 between the HV side 122 and the LV side124. Also shown is the longitudinal axis L of the integrated circuitpackage 110, between internal edges (pads) of the HV side 122 and the LVside 124. If FIG. 5 illustrated a complete representation of thesemiconductor integrated circuit package 110, rather than just the leadframe 112, the integrated circuit package 110 shown in the cross-sectionof FIG. 3 would be located at line 3-3 of FIG. 5.

FIG. 6 illustrates a perspective view of the lead frame 112 of FIG. 5,further showing a S/R dam 350 located thereon. In this aspect, the S/Rdam 350 is referred to a T-dam, due to a shape of the S/R dam 350 inspanning certain portions of the HV side 122 and the LV side 124 of thelead frame 112. In other aspects, the S/R dam 350 may be I-shaped or maybe one of various other shapes. Again, if FIG. 6 illustrated a completerepresentation of the semiconductor integrated circuit package 110,rather than just the lead frame 112 and the S/R dam 350, the integratedcircuit package 110 shown in the cross-section of FIG. 3 would belocated at line 3-3 of FIG. 6.

FIG. 7 illustrates, from an opposite end, a perspective view of the leadframe 112 of FIG. 6. FIG. 7 again shows the S/R dam 350 on the leadframe 112 (i.e., the S/R dam 350 only, without a die thereon). FIG. 7illustrates the S/R dam 350 in transparent fashion, allowing see-throughto illustrate example spanning (and overlap) of various portions of theHV side 122 and the LV side 124 of the lead frame 112 by the S/R dam350. Note that in the FIG. 7 example, the S/R dam 350 not only spans(overlaps) the HV side 122 and the LV side 124 across a width of the P2Pspace 126 (i.e., perpendicular to the longitudinal axis L), at locationsA and B, but the S/R dam 350 spans (overlaps) the HV side 122 and the LVside 124 (i.e., perpendicular to the longitudinal axis L) across variouswidths of the space between the HV side 122 and the LV side 124 atvarious locations along the longitudinal axis L (for example, atlocations C and D; and E and F). In addition, the S/R dam 350 spans(overlaps) each of the HV side 122 and the LV side 124 in certainlocations in a direction parallel to the longitudinal axis L (forexample, at location G and H). Again, if FIG. 7 illustrated a completerepresentation of the semiconductor integrated circuit package 110,rather than just the lead frame 112 and the S/R dam 350, the integratedcircuit package 110 shown in the cross-section of FIG. 3 would belocated at line 3-3 of FIG. 7. The perspective end viewed in FIG. 7 isconsistent with the side shown in the cross-section view of FIG. 3.

FIG. 8 illustrates, from an underside perspective view, the S/R dam 350relative to, and within an area of, the die 114, along with partialportions of the lead frame 112, showing partial portions of the HV side122 and the LV side 124. FIG. 8 highlights how the S/R dam 350, lyingwithin an area of the die 114, creates an overhang 860 of the die 114 oneach side of a width dimension of the dam 350 (i.e., perpendicular tothe longitudinal axis L), when the S/R dam 350 is attached to, or isarranged relative to, the die 114. FIG. 8 also shows how the S/R dam350, lying within an area of the die 114, creates an overhang 860 of thedie 114 along a length dimension of the dam 350 (i.e., parallel to thelongitudinal axis L), when the S/R dam 350 is attached to, or isarranged relative to, the die 114. FIG. 8 illustrates an exampleT-shaped S/R dam 350. Other S/R dam 350 and overhang 860 configurationsare possible (e.g., an I-shaped S/R dam 350).

FIG. 9 illustrates a perspective view (but closer to an elevation view)of an example (and partial) semiconductor integrated circuit package110, showing the die 114 on the S/R dam 350, with the S/R dam 350 on andoverlapping the HV side 122 and the LV side 124 of the lead frame 112.The S/R dam 350, spanning across the HV side 122 and the LV side 124 ofthe lead frame 112 prevents the adhesive resin, located beneath theoverhang 860 (or in the gap between the die 114 and a respective HV side122 and/or LV side 124 of the lead frame 112), from bleeding into theP2P spacing 126 between the HV side 122 and the LV side 124.

The above discussion is meant to be illustrative of the principles andvarious examples of the disclosure. Numerous variations andmodifications will become apparent to those skilled in the art once theabove disclosure is fully appreciated. It is intended that the followingclaims be interpreted to embrace all such variations and modifications.

1. An apparatus, comprising: a lead frame; a dam and adhesive onportions of the lead frame; and an integrated circuit die having aportion on the dam and another portion on the adhesive, wherein the leadframe includes two lead frames.
 2. (canceled)
 3. The apparatus of claim1, wherein the dam bridges a space between the two lead frames.
 4. Theapparatus of claim 3, wherein the dam is smaller than the integratedcircuit die in at least a width dimension of the dam relative to a widthdimension of the integrated circuit die, wherein the integrated circuitdie overhangs the dam on each side of the width dimension of the dam. 5.The apparatus of claim 1, wherein the dam is smaller than the integratedcircuit die in at least a width dimension of the dam relative to a widthdimension of the integrated circuit die, wherein the integrated circuitdie overhangs the dam on each side of the width dimension of the dam. 6.The apparatus of claim 1, wherein adhesive is located between theintegrated circuit die and the lead frame, adjacent to and on each sideof the dam.
 7. The apparatus of claim 1, wherein the dam is a dry film.8. (canceled)
 9. The apparatus of claim 1, wherein the dam is smallerthan the integrated circuit die in a length dimension of the damrelative to a length dimension of the integrated circuit die, over atleast a portion of the dam and of the integrated circuit die, whereinthe integrated circuit die overhangs the dam over at least the portionof the dam and of the integrated circuit die.
 10. The apparatus of claim9, wherein adhesive is located between the integrated circuit die andthe lead frame, adjacent to and on a side of the dam, due to the dambeing smaller than the integrated circuit die in the length dimension ofthe dam relative to the length dimension of the integrated circuit dieover at least the portion of the dam and of the integrated circuit die.11. The apparatus of claim 3, wherein the dam is smaller than theintegrated circuit die in a length dimension of the dam relative to alength dimension of the integrated circuit die, over at least a portionof the dam and of the integrated circuit die, wherein the integratedcircuit die overhangs the dam over at least the portion of the dam andof the integrated circuit die.
 12. The apparatus of claim 11, whereinadhesive is located between the integrated circuit die and the leadframe, adjacent to and on a side of the dam, due to the dam beingsmaller than the integrated circuit die in the length dimension of thedam relative to the length dimension of the integrated circuit die overat least the portion of the dam and of the integrated circuit die. 13.An apparatus, comprising: a lead frame including two die attach pads,each of the two die attach pads electrically connected to at least onelead of a plurality of leads; a dam and adhesive on portions of the leadframe; and an integrated circuit die having a portion on the dam andanother portion on the adhesive; wherein: the dam is smaller than theintegrated circuit die in a width and length dimension of the damrelative to the integrated circuit die, over at least a portion of thedam and the integrated circuit die, wherein the integrated circuit dieoverhangs the dam in each location where the dam is smaller than theintegrated circuit die in the width or the length dimension; the dam andthe integrated circuit die bridge a space adjacent to a side of the leadframe; adhesive is located between the integrated circuit die and thelead frame, adjacent to and on each side of the dam, due to the dambeing smaller than the integrated circuit die in the width and thelength dimension, whereby the dam prevents adhesive from spreading intothe space adjacent to the side of the lead frame. 14-20. (canceled) 21.An apparatus, comprising: two die attach pads, each of the two dieattach pads electrically connected to at least one lead of a pluralityof leads; a dam and an adhesive on portions of the two die attach pads;and an integrated circuit die having a portion on the dam and anotherportion on the adhesive.
 22. The apparatus of claim 21, wherein the dambridges a gap between the two die attach pads.
 23. The apparatus ofclaim 21, wherein the integrated circuit die is electrically connectedto at least one of the plurality of leads.
 24. The apparatus of claim21, wherein the dam is smaller than the integrated circuit die in atleast a width dimension of the dam relative to a width dimension of theintegrated circuit die, wherein the integrated circuit die overhangs thedam on each side of the width dimension of the dam.
 25. The apparatus ofclaim 21, wherein the dam is a dry film.
 26. The apparatus of claim 21,wherein a plane along a surface of the adhesive is coplanar with a planealong a surface of the dam.
 27. The apparatus of claim 21, wherein onedie attach pad of the two die attach pads is at a low voltage side ofthe apparatus and the other die attach pad of the two die attach pads isat a high voltage side of the apparatus.